What do I need to use TeamSpeak with World of Warcraft?

There are two different types of microphones. USB headet-microphone and wired microphone.
If you do not have a USB headset, plug your microphone(usually a pink plug) into the pink socket on the back of your computer.

If you have a USB headset (metal rectangular plug) plug the connection into the back of your computer in the USB connector it fits into.

A TeamSpeak Server to connect to.
Details...

You will need the server address and password (if there is a password needed to join) of the TeamSpeak Server you are joining.
Example: ts7.light-speed.com:8163 (The IP/Hostname is ts7.light-speed.com, The port is 8163. Together they form the Server Address)